Montelukast

UNDER REVIEW (September 2016)

Mechanism of Action:

Cysteinyl-leukotriene receptor antagonist, anti-inflammatory action [leukotriene antagonist]. Leukotriene such as LTC4 and LTD4 are spasmogens (cause smooth muscle in airways to contract and become “twitchy” or hypersensitive).

Lecture and CAL materials:

Ipratropium

UNDER REVIEW (September 2016)

Mechanism of Action:

Ipratropium is an antagonist at muscarinic acetylcholine receptors (mAChR)(m3 subtype). Muscarinic AChRs are transmembrane G-protein coupled receptors (GPCRs) which are activated by the endogenous neurotransmitter, acetylcholine, the key transmitter in the parasympathetic nervous system, and also a major transmitter in the CNS. Another well-known muscarinic antagonist is atropine.

Lecture and CAL materials:

Theophylline

UNDER REVIEW (September 2016)

Mechanism of Action:

Theophylline is a xanthine derivative drug that has a structural and pharmacological similarity to caffeine. It is naturally found in black tea and green tea. The mechanism of action is probably by inhibition of phosphodiesterase (PDE), an enzyme that breaks down the secondary messenger cyclicAMP. Potentiation of cAMP, the secondary messenger for beta-adrenoreceptors, leads to smooth muscle relaxation. Some of the effects of theophylline are therefore similar to beta-agonists. The main actions of theophylline are (1) relaxation of bronchial smooth muscle, (2) positive inotropic – increases heart muscle contractility and efficiency(3) positive chronotropic – increases heart rate, (4) lowers blood pressure, (5) increases renal blood flow, and (6) some anti-inflammatory effect. Theophylline may also antagonise the effects of adenosine.

Lecture and CAL materials:

Oxygen

UNDER REVIEW (September 2016)

Mechanism of Action:

Oxygen is a naturally occurring gas that is vital for life in all aerobic cells. Its tetravalent reduction to water in the mitochondrial electron transport chain provides the energy for all cellular activities. It is normally found at a partial pressure of 13KPa in arterial blood which is equivalent to 99% saturation of haemoglobin. In several cardiac and respiratory disease states gas exchange in the lung is impaired leading to arterial hypoxaemia. This reduction in oxygen carriage and delivery to cells can be partially reversed by increasing the inspired oxygen concentration above the 20% found in room air with supplementary oxygen. Oxygen should be regarded as a drug.

Lecture and CAL materials: